Quick-dump free-surface stabilizer

ABSTRACT

A free-surface stabilizer particularly suited for use on vessels such as off-shore supply boats and ferries. The stabilizer takes the form of a liquid-tight rectangular tank extending across the beam of the associated vessel. The port and starboard walls of the tank are provided with hinged liquid-tight doors pneumatically controlled at a remote location. Upon activation of a pneumatic system, the port and starboard doors of the tank are opened and the stabilizing liquid spills from the tank and into the sea in a matter of seconds. In this manner, the free-surface moment is quickly eliminated, and the GM of the vessel is quickly increased.

United States Patent 1191 Brunsell Nov. 13, 1973 QUICK-DUMP FREE-SURFACE STABILIZER Primary Examiner-Milton Buchler [75] Inventor: Paul A. Brunsell, Massapequa, Long jif fi i M' Goldstem Island, NY orneyarm e1 e a.

[73] Assignee: Flume Stabilization Systems, Inc.,

Hoboken, NJ. [57] ABSTRACT A free-surface stabilizer particularly suited for use on [22] 1972 vessels such as off-shore supply boats and ferries. The [21] Appl. No.: 218,915 stabilizer takes the form of a liquid-tight rectangular tank extending across the beam of the associated vessel. The port and starboard walls of the tank are proll4lli5slbljlg vided with hinged liquid tight doors pneumatically [58] g 78 controlled at a remote location. Upon activation of a 0 care pneumatic system, the port and starboard doors of the tank are opened and the stabilizing liquid spills from R Cit d the tank and into the sea in a matter of seconds. In

e erences e this manner, the free-surface moment is quickly elimi- UNITED STATES PATENTS nated, and the GM of the vessel is quickly increased. 3,504,651 4/1970 Halden et al. 114/125 1,835,686 12/1931 Allan et al. 114/117 15 3 Drawmg Flgures QUICK-DUMP FREE-SURFACE STABILIZER BACKGROUND OF THE INVENTION The United States Coast Guard requires all ships to have a minimum GM, based upon weather (wind) criteria and on damaged stability. Some vessels, such as off-shore supply boats and ferries, very often operate with marginal stability because of their shape and loading arrangement. Accordingly, vessels of this type have heretofore been unable to use passive free-surface tank roll stabilizers; the reduction in static GM resulting from the inclusion of a tank stabilizer would cause the GM to fall below the minimum allowable by the Coast Guard.

It is toward the provision of a passive free-surface tank roll stabilizer for use on vessels such as off-shore supply boats and ferries, that the present invention is directed.

SUMMARY OF THE INVENTION The present invention relates to a rectangular passive free-surface rol-l stabilizing tank particularly suitable for use aboard vessels such as off-shore supply boats and ferries. While the provision of the inventive freesurface tank aboard such vessels reduces the static GM, the tank is provided with doors at the port and starboard ends which, when opened, empty the stabilizing liquid into the sea within a matter of seconds. Accordingly, if the weather should change or if the vessel should become damaged, the free-surface moment may be eliminated almost instantaneously, thereby bringing the vessels GM to a safe value.

With the present invention, a passive free-surface tank stabilizer may, for the first time, safely be used aboard vessels such as off-shore supply boats and ferries. Accordingly, the present invention, for the first time, permits supply boats and ferries to enjoy the advantages of free-surface stabilization without the worry of the free-surface moment detrimentally affecting the stability of the vessel.

It is accordingly the main object of the present invention to provide a passive free-surface tank stabilizer particularly suited for safe use aboard vessels such as off-shore supply boats and ferries.

A further object of the present invention is to provide a passive free-surface tank stabilizer which may be emptied within a matter of seconds.

Still another object of the present invention is to provide a passive free-surface tank stabilizer which allows vessels such as supply boats and ferries to enjoy the benefits of stabilization when conditions permit, yet which can substantially instantaneously eliminate its free-surface moment when necessary.

A more specific object of the present invention is to provide a passive free-surface tank stabilizer having hinged doors on the port and starboard sides thereof which operate in response to a remote pneumatic control to empty the tank in a matter of seconds.

These and other objects of the present invention, as well as many of the attendant advantages thereof, will become more readily apparent when reference is made to the following description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a portion of an offshore oil-rig supply vessel equipped with a passive freesurface tank stabilizer constructed in accordance with the teachings of the present invention;

FIG. 2 is a perspective view showing one end ofa stabilizer constructed in accordance with the teachings of the present invention; and

FIG. 3 is a perspective view similar to FIG. 2, but showing the stabilizer when emptying its stabilizing liquid.

DETAILED DESCRIPTION OF THE DRAWINGS With reference first to FIG. 1, the arrangement of the inventive stabilizer will be described. A small vessel, such as an offshore oil-rig supply boat, is shown gener ally at 10. The bridge deck of the boat is indicated at 12 and serves as a base for the inventive stabilizer shown generally at 14. As can be seen in FIG. 1, the stabilizer 14 is generally rectangular in cross-section and extends substantially from the port to starboard sides of the boat 10. The stabilizer 14 is liquid-tight and houses a body of stabilizing liquid, such as water, whose level is shown at 16 in FIG. 2. Hinged, water-tight doors 18 (one being shown in FIG. 1) are provided in the port and starboard ends of the stabilizing tank 14. And each door 18 associates with a pneumatic release mecha nism shown generally at 20.

Now, with reference to FIGS. 2 and 3, the details of the pneumatically operated doors 18 will be described. Each of the port and starboard doors 18 is hinged to a respective outboard wall 22 of the stabilizing tank 14. Three hinges 24 are illustrated at the top of the door 18. A pair of pneumatically operated locking assemblies 26 is positioned at the lower portions of the respective doors 18. And a gasket 28 serves as a liquidtight seal between the walls 22 of the tank 14 and the respective doors.

Each locking assembly 26 is basically of two-element construction. The first element takes the form of a mounting block 30 rigidly secured to the wall 22 of the tank 14, on which mounting block 30 is secured to an abutment surface 32. The second element of each locking assembly 26 takes the form of a latch 34 pivotally mounted on a pin or shaft 36. A linkage 38 connects the two latches 34 of the locking assemblies 26 at the tops thereof by means of pivot pins 40. And as can be seen in FIGS. 2 and 3, the shafts 36, and hence the latches 34, are mounted on the respective doors 18.

Each of the pneumatic release mechanisms 20 derives its power from a control system (not shown) and through a delivery line 42. The function of each release mechanism is to control the position of its associated piston element 44 in a pneumatic chamber 46. Each piston 44 is connected to a linkage 38, via lever 48, by means of a pin 50.

The operation of each of the pneumatically controlled doors 18 is as follows. FIG. 2 illustrates the position of a door 18 when the passive free-surface stabilizing tank 14 is operative. As illustrated, the pneumatic system is relaxed, with piston 44 in its rest position. When so oriented, the linkage 38 maintains the respec tive latches 34 in alignment with the abutment surfaces 32 on the associated mounting blocks. Accordingly, the door 18 is maintained in its sealed position against the outboard wall 22 of the tank 14.

When it is desired to drain the tank of its stabilizing liquid, as when weather conditions change for the worse or if the associated vessel is damaged, the pneumatic control system is activated. Air is forced through delivery line 42 and into the pneumatic chamber 46. In response to the air reaching the chamber 46, the piston 44 is urged in the direction of arrow 52. And as the piston 44 moves in the direction of arrow 52, so too does linkage 38. Accordingly, respective latches 34 are rotated in a counterclockwise direction about their respective shafts 36. The lower part of the latches 34 are hence moved out of the area of the abutment surfaces 32, and the respective doors 18 are allowed to open. In response to the substantial pressure head developed on the inside of the doors 18, the doors open and the stabilizing liquid is immediately expelled. This is shown by arrow 54 in FIG. 3. In view of the relatively large size of the doors 18, it should be appreciated that the stabilizing liquid may be expelled from the tank 14 in a matter of seconds. Accordingly, if the ship should experience damage, or if the weather conditions should change, the free-surface moment associated with the stabilizing liquid could almost instantaneously be eliminated.

Above, a specific embodiment of the inventive passive free-surface stabilizer has been described. It should be appreciated, however, that this embodiment has been described for purposes of illustration only, and that many alterations and modifications may be practiced by those skilled in the art without departing from the spirit or scope of the invention. For example, while the hinges 24 have been shown to be passive, with thedoors 18 opening as a result of the internal pressure head, the hinges may be made active or the opening of the doors may be accomplished by an independent power source. And while the power release mechanisms have been illustrated as pneumatically operated, the powering may take many other forms. Many other modifications are apparent and within the skill of the marine engineer. Accordingly, it is the intent that the present invention not be limited by the above, but be limited only as defined in the appended claims.

What is claimed is:

1. A passive free-surface stabilizing tank system for stabilizing a vessel against roll and capable of emptying its supply of stabilizing liquid in a matter of seconds, the-system comprising: a rectangular, liquid-tight tank located above the deck of an associated vessel and extending substantially from the port to the bridge starboard sides of the vessel; a body of stabilizing liquid housed in said tank and adapted to develop a moment to stabilize the vessel against roll; at least one door in a wall of said tank of a size so that, when opened, the tank discharges its stabilizing liquid above the deck and over at least one side of the vessel in a matter of seconds; seal means to ensure liquid-tight cooperation between said door and the associated wall of said tank when the door is closed; and release means for opening said door to discharge the stabilizing liquid from said tank.

2. The stabilizing tank system recited in claim 1, wherein one door is provided on each of the port and starboard walls of said tank.

3. The stabilizing tank system recited in claim 2, wherein each door is of a size substantially the same as its associated tank wall.

4. The stabilizing tank system recited in claim 1, and further comprising means for remotely operating said release means.

5. The stabilizing tank system recited in claim 4, and further comprising means for pneumatically controlling said release means.

6. The stabilizing tank system recited in claim 1, wherein said door is hinged to its associated tank wall at the .top thereof.

7. The stabilizing tank system recited in claim 6, and further comprising means for remotely operating and pneumatically controlling said release means.

8. The stabilizing tank system recited in claim 7, wherein said release means takes the form of at least one latch which, in its rest position, maintains its associated door in liquid-tight communication with the tank wall on which it is mounted; and an abutment surface for engaging said latch when in its rest position.

9. The stabilizing tank system recited in claim 8, wherein the means for remotely oerating and pneumatically controlling said release means initiates a change in the position of said latch so as to release its associateddoor from liquid-tight communication with the tank wall on which it is mounted.

10. The stabilizing tank system recited in claim 9, wherein said latch is provided at the bottom of said door.

11. The stabilizing tank system recited in claim 10, wherein said latch is mounted on said door and wherein said abutment surface is mounted on the associated wall of the tank.

12. The stabilizing tank system recited in claim 1, wherein one door is provided on each of the port and starboard walls of said tank; wherein each of said doors is hinged to its associated tank wall at the top thereof; wherein said release means associates with said doors at the respective bottoms thereof; and wherein each of said release means comprises a pivotally mounted latch and an associating abutment surface for engaging said latch.

13. The stabilizing tank system recited in claim 12, wherein each of said latches is pivotally mounted on its associated door; and wherein each of said abutment surfaces is mounted on its associated tank wall.

14. The stabilizing tank system recited in claim 13, wherein each of said doors is provided with two release means; and further comprising a linkage communicating the latches of said two release means; and a remote control means for operating said linkage.

15. The stabilizing tank system recited in claim 14 and further comprising pneumatic means for operating said remote control means. 

1. A passive free-surface stabilizing tank system for stabilizing a vessel against roll and capable of emptying its supply of stabilizing liquid in a matter of seconds, the system comprising: a rectangular, liquid-tight tank located above the deck of an associated vessel and extending substantially from the port to the bridge starboard sides of the vessel; a body of stabilizing liquid housed in said tank and adapted to develop a moment to stabilize the vessel against roll; at least one door in a wall of said tank of a size so that, when opened, the tank discharges its stabilizing liquid above the deck and over at least one side of the vessel in a matter of seconds; seal means to ensure liquid-tight cooperation between said door and the associated wall of said tank when the door is closed; and release means for opening said door to discharge the stabilizing liquid from said tank.
 2. The stabilizing tank system recited in claim 1, wherein one door is provided on each of the port and starboard walls of said tank.
 3. The stabilizing tank system recited in claim 2, wherein each door is of a size substantially the same as its associated tank wall.
 4. The stabilizing tank system recited in claim 1, and further comprising means for remotely operating said release means.
 5. The stabilizing tank system recited in claim 4, and further comprising means for pneumatically controlling said release means.
 6. The stabilizing tank system recited in claim 1, wherein said door is hinged to its associated tank wall at the top thereof.
 7. The stabilizing tank system recited in claim 6, and further comprising means for remotely operating and pneumatically controlling said release means.
 8. The stabilizing tank system recited in claim 7, wherein said release means takes the form of at least one latch which, in its rest position, maintains its associated door in liquid-tight communication with the tank wall on which it is mounted; and an abutment surface for engaging said latch when in its rest position.
 9. The stabilizing tank system recited in claim 8, wherein the means for remotely oerating and pneumatically controlling said release means initiates a change in the position of said latch so as to releasE its associated door from liquid-tight communication with the tank wall on which it is mounted.
 10. The stabilizing tank system recited in claim 9, wherein said latch is provided at the bottom of said door.
 11. The stabilizing tank system recited in claim 10, wherein said latch is mounted on said door and wherein said abutment surface is mounted on the associated wall of the tank.
 12. The stabilizing tank system recited in claim 1, wherein one door is provided on each of the port and starboard walls of said tank; wherein each of said doors is hinged to its associated tank wall at the top thereof; wherein said release means associates with said doors at the respective bottoms thereof; and wherein each of said release means comprises a pivotally mounted latch and an associating abutment surface for engaging said latch.
 13. The stabilizing tank system recited in claim 12, wherein each of said latches is pivotally mounted on its associated door; and wherein each of said abutment surfaces is mounted on its associated tank wall.
 14. The stabilizing tank system recited in claim 13, wherein each of said doors is provided with two release means; and further comprising a linkage communicating the latches of said two release means; and a remote control means for operating said linkage.
 15. The stabilizing tank system recited in claim 14 and further comprising pneumatic means for operating said remote control means. 